Process for removing mercaptans from a gas stream
AssigneeShell Oil Company
InventorsJozef Jacobus Titus Smits, Sipke Hidde Wadman
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Abstract
The present invention provides a process for removing mercaptans from a gas stream gas stream, comprising the steps: a) providing a first mercaptan-comprising gas stream comprising at least a mercaptan of the general formula: R1—SH, wherein R1 is an alkyl group comprising 1 to 4 carbon atoms; and b) contacting the mercaptan-comprising gas stream with an absorption medium comprising a substituted disulphide and a nitrogen-containing base to obtain a second mercaptan-depleted gas stream, wherein: the substituted disulphide is of the general formula R2—SS—R3 wherein: R2 and R3 are carbon comprising substituents of which the corresponding R2—SH and R3—SH thiols have a vapor pressure below the vapor pressure of any R1—SH thiol.
Claims12
A process for removing mercaptans from a gas stream gas stream, comprising the steps:
- a) providing a first mercaptan-comprising gas stream comprising at least a mercaptan of the general formula:
- R1—SH,
- wherein R1 is an alkyl group comprising 1 to 4 carbon atoms;
- and
- b) contacting the mercaptan-comprising gas stream with an absorption medium comprising a substituted disulphide and a nitrogen-containing base to obtain a second mercaptan-depleted gas stream,
- wherein:
- the amount of the substituted disulphide used in the absorption medium is chosen on the basis of at least equimolarity to the amount of the mercaptan that is to be removed;
- and
- at least a catalytic amount of the nitrogen-containing base is present in the absorption medium;
- and
- the substituted disulphide is of the general formula
- R2—SS—R3
- wherein:
- R2 and R3 are carbon comprising substituents of which the corresponding R2—SH and R3—SH thiols have a vapour pressure below the vapour pressure of any R1—SH thiol;
- and
- at least one of R2 and R3 is an electron withdrawing group.
A substituted disulphide solution, comprising:
- a. a substituted disulphide of the general formula:
- R2—SS—R3
- wherein:
- R2 and R3 are carbon comprising substituent of which the corresponding R2—SH and R3—SH thiols have a vapour pressure below the vapour pressure of any butyl-SH thiol, and at least one of R2 and R3 is an electron withdrawing group, and
- b. an aliphatic alkanolamine,
- wherein
- the amount of the substituted disulphide constitutes from 1 to 10 mass % of the substituted disulphide solution;
- and
- the aliphatic alkanolamine is present in the substituted disulphide solution at least 3 mol % with regard to the amount of the substituted disulphide.
Dependencies are inferred from the claim text.